000
FXUS63 KDMX 190907
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
407 AM CDT SUN MAY 19 2013

.DISCUSSION.../TODAY THROUGH SATURDAY/...
ISSUED AT 407 AM CDT SUN MAY 19 2013

AMPLE WEATHER DURING THE FORECAST PERIOD WITH ONGOING CONVECTION
PASSING THROUGH THE FORECAST AREA. THIS ARC OF THUNDERSTORMS IS
EXPECTED TO PROGRESS NORTHEAST OUT OF THE AREA TOWARD 12Z. THERE
MAY BE SOME LINGERING CONVECTION...HOWEVER IT APPEARS THERE WILL
BE SOME DOWN TIME DURING THE DAY WITH WEAK SUBSIDENCE ON THE
BACKSIDE OF THIS CONVECTION THIS MORNING. THIS SHOULD ALLOW DAYTIME
HEATING TO PROGRESS WITH INSTABILITY INCREASING THROUGHOUT THE
DAY. WILL ALSO SEE SHEAR BEGIN TO INCREASE AS MID LEVEL SPEED MAX
APPROACHES LATE IN THE DAY. POTENTIAL FOR SEVERE WEATHER LOOKS
GOOD BY LATE AFTERNOON INTO THE EVENING WITH BEST PARAMETERS
ACROSS THE SOUTH. ALL MODES OF SEVERE WEATHER WILL BE POSSIBLE
INCLUDING LARGE HAIL...DAMAGING WINDS WITH A FEW TORNADOES ALSO
POSSIBLE...ESPECIALLY IN THE SOUTH AND WEST.

THE CONVECTION WILL PULL NORTHEAST ACROSS CENTRAL IOWA TONIGHT AS
SHORTWAVE MOVES QUICKLY THROUGH THE STATE. WILL LIKELY SEE
CONVECTION DIMINISH OVER THE FORECAST AREA LATE TONIGHT AS DRIER
AIR ALOFT MOVES ACROSS THE STATE. EXCEPTION WOULD BE IN THE FAR
NORTH WHERE FORCING LINGERS AND CONVECTION MAY PERSIST FOR MUCH OF
THE NIGHT. WILL CONTINUE TO MONITOR THIS AREA FOR POTENTIAL HEAVY
RAINFALL AND THE POSSIBILITY OF FLASH FLOODING GIVEN THE PREVIOUS
HEAVY RAINS OF EARLIER IN THE WEEK.

UPPER LOW WILL SIT AND SPIN FOR THE EARLY PART OF THE WEEK
BRINGING CHANCES OF CONVECTION ON MONDAY INTO TUESDAY WITH
ADDITIONAL THREAT OF SEVERE WEATHER...MAINLY EAST DURING THIS
TIME AS MOISTURE AND SHEAR REMAIN IN PLACE. UPPER SYSTEM WILL
EVENTUALLY PULL AWAY LATER IN THE WEEK WITH DRIER WEATHER INTO
THURSDAY AND FRIDAY. HOWEVER...THE BREAK APPEARS SHORT LIVED AS
WARM ADVECTION AND MOISTURE TRANSPORT INCREASE LATE FRIDAY INTO
SATURDAY. THIS WILL BRING ADDITIONAL CHANCES FOR THUNDERSTORMS
LATE IN THE PERIOD.

&&

.AVIATION...19/06Z
 ISSUED AT 1152 PM CDT SAT MAY 18 2013

LINE OF STORMS BEGINNING TO CROSS THE IA/NE BORDER WITH A SECOND
SEGMENT COMING UP FROM KS.  THE LINE OF STORMS OVER NE SHOULD WEAKEN
WHILE THE STORMS OVER KS SHOULD LIFT ACROSS CENTRAL IOWA THROUGH
12-15Z.  HEAVY RAIN POTENTIAL WITH THESE STORMS AS WELL AS AN
ISOLATED STRONG WIND OR LARGE HAIL THREAT BUT STORMS WILL BE LIFTING
INTO A LITTLE LESS FAVORABLE AIR.  I AM EXPECTING A BREAK FROM
15Z-19Z BUT HOW FAST WE BREAK OUT OF THE CLOUDS AND DESTABILIZE WILL
PLAY A ROLE IN HOW QUICKLY STORMS REDEVELOP.  A STRONG UPPER LEVEL
FEATURE WILL MOVE IN BY 21Z AND SWING NE THROUGH THE END OF THE TAF
PERIOD BRINGING ANOTHER ROUND OF THUNDERSTORMS...SOME WITH THE
POTENTIAL FOR DAMAGING WIND AND LARGE HAIL.  THE BEST THREAT WOULD
BE OVER KDSM WITH KOTM AND KFOD ON THE FRINGE OF THE THREAT AREA.


&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

DISCUSSION...COGIL
AVIATION...FAB